Centrifugal clutch construction



Nov. 25, 1941. F. KREIS GENTRIFUGAL CLUTCH CONSTRUCTION Filed Jan. 18, 1940 a Sheets-Sheet 1 s ul Nbv..25, 1941. KREls 2,263,702

CENTRIIFUGALJCLUTCH CONSTRUCTION Filed Jan. 18,- 1940 3 Sheets-Sheet 2 Nov. 25, 1,941. .5 KRBS 2,263,702

I CENTRIFUGAL CLUTCH CONSTRUCTION Filed Jan. 18, 1940 3 Sheets-Sheet 3 Patented Nov. 25, 1941 I UNITED STATES PATENT OFFICE' 4 antenna CENTRIFUGAL c u'rcn cous'muorron Fri edrich- Kreis, fierlin-Licliterfelde, Germany,

assignor to Gesellschaft zurKonstruktion und Verwertung Automatisch-Mechanischer' Getriebe m. b'.

many

11., Berlin-Oberschoneweide, Ger- Appllcation January 1a, 1940, Serial No. 314,534 In Germany January 18, 1939 13 Claims. (01. 192-155) The present invention relates toimprovements larly-to centrifugal clutches designed for use in automatic change, speed transmissions for motor vehicles. a

An object of the invention is to provide, a more compact and efficient centrifugal clutch construction in which the spring retracted centrifugal weights are arranged between axially movable clutch plates and operate to draw the late in centrifugal clutch construction and particu Experiments have shown that with such a mounting itis possible for the clutch to be disengaged earlier with a higher loading moment.

Control of the application pressure by the centrifugal weights can be accomplished in the clutch; according ,to the invention in various ways." For instance, it is possible to allow the 'controlof the application pressure to occur ter toward each other to release the clutch against the force of expansion springs which normally tend to separate the plates and engage the clutch, the weights being connected with said plates so as to permit separation of said plates and engagement of the clutch by said expansion springs when the weights @move outwardly-under the influenc of' centrifugal force.

Centrifu gal clutches have been proposed in which" the application pressure is produced by spring force while the centrifugal weights are used only for freeing the path for the clutch springs; for producing the application pressure. These clutches however are basically different from that of the present invention, the centrifugalLweights are not arranged between the clutch plates and do not move in a path parallel to the clutch plates but on the contrary they are through the medium of slot guides for the centrifugal weight suspension members, said slots overlapping each other and carried bylthe clutch plates. The control of the application pressure may also be accomplished by means of threaded sleeves operated by the centrifugal weights and provided .at one end with right-hand .screwthreads and at the other end with left-hand screwthreads in which threaded studs secured to the inside of the respective oppositely disposed. clutch plates engage. The clutch plates are preferably guided by means of telescoping bushings carried'thereby and disposed between adjacent screw connections,- these bushings serving at the" .same time as mounts for the swinging arms usually located outside the clutch plates and oscillate on axes parallel to the clutch plates so that they require a much greater space. Prior clutches of this type are not suitable to be built into a compact structure together with a numberof similar clutches as is required for instance in a multistage automatically shifting gear-wheel change speed gearing, each stage of which is connected to the engine through aseparatejointed to the centrifugal weights.- The threaded studs arranged on the inside of the clutch plates and en'saging'the threaded sleeves preferably are made hollow, and both these and the aforementioned guide bushings each enclose a compression spring for exerting .the application pressure.

The disengagement of the clutch at a lower number of rev olutions than the engagement can clutch. The clutches already known therefore cannot be used for a gearing of that kind but are adaptable only as a substitute for the ordin ary engine clutch used with hand-shifted gearings.

The centrifugal clutch according to the prespended from the same so-that they move out contrary to the direction of rotation of the clutch.

be attained by arranging the swinging'arms, connected by a pivoted joint to the centrifugal weights, so as to swing out to the neutral positionof equilibrium during engagementof the clutch, the weights being started back from the neutral position by a return pulling force .eflec tive onlyat a lower speed of rotation than that necessary to effect engagement. For this purpose, in accordance with one form of the invention, the levers carrying the centrifugal weights or a part of the same, are connected through additional levels with centrifugal weights of an ,inner centrifugal weight ring, likewise divided up into segments and biased to retracted position by a constricting spring, so that upon movement of these latter centrifugal weights towards the 1 inside at reduced speed, a stop connected to the additional levers instigatesthe return movement of the levers connected to the main centrifugal weights. According to another form of the invention the swinging arms that are connected by pivotal joints to the centrifugal weights controlling the application pressure can be swung out operating members in and releasing can engage behinda detent provided on the swinging arm. I

The invention will be described more in detail in connection with the accompanying drawings in which preferred constructional forms are illustrated.

,In the drawings:

Fig. 1 is an axial section through a centrifugal weight clutch embodying the invention and which may be employed, for instance, for shifting direct ear; g Figs. 2 and 3 are each a cross-section of the same on the line 2-4 of Fig. 1, showing the same in disengaged and engaged condition respectively; Figs. 4 and 5 are details of the slot guide for the centrifugal weight suspension in the disengaged and engaged condition respectively;

Fig. 6 is an axial section through a clutch embodying a modified means for holding the clutch them from engaging position;

Fig. 7 is a sectional view on the line 1-1 of Fig. 6, showing the clutch disengaged; f Fig. 8 is a similar view showing the position of the parts when the clutch is engaged;

Fig. 9 is a transverse section on the line 9-.9 of Fig. 10 illustrating another modification; ,Fig. 10 is an axial section thereof;

Fig. 11 is a section on the line Il--l I of Fig. 9, with parts in elevation, and

Fig. 12 is a fragmentary view, similar to Fig. 9, showing the position of the parts when the clutch is in engagement.

Referring to Figs. 1, 2 and 3, the flywheel of the engine is constructed-so as to act also as the outer element or drum i of the clutch. The drum l is partially closed on the outside by a ring 2. Annular clutch plates 3 and 4 of ring form, on which the friction clutch surfaces 5 and 6 in ring form are carried, are taken along by bolts 1 mounted on the clutch hub 8. The clutch hub 8 is rigidly connected to the driven shaft 9. Between the axially movable clutch plates 3 and 4 are inserted a plurality of application pressure springs in disposed in symmetrical arrangement, these being compressed in the disengaged state of the clutch as shown in Figs. 1 and 2. Fig. 3 shows the engaged condition of the clutch, wherein the application pressure springs in are partly expanded and thereby produce the coupling pressure between the plates 3 and 4 and the drum l. The release and tensioning of the springsli'l and resultant shifting of the plates 3- and 4 is caused by a play of forces between the centrifugal force of the centrifugal weights II on the one hand and the. constricting force of the constricting springs l2 on the other hand, the latter serving to bias the weights to retracted position. If the clutch turns in the direction of the arrow A (Figs. 2 and 3), the weights ll swing out in the opposite direction uponthe attainment of suflicient speed to effect engagement of the clutch. If suddenly, the driving moment to be transferred to the clutch drum l is increased by hill travel or sudden application of the brakes to the vehicle, then,

about the bolts I, the levers being pivoted on the bolts 1 and the weights connected thereto by pins l3. The levers l4 extend through oppositely slanting cam slots in two overlapping annular flanges of angular rings l5 and I6 that are rigidly connected to the inner faces of clutch plates 3 and i 4. Bearing rollers I1 and I8 mounted to turn on levers l 4 are arranged to engage the slanting sides l9 and 20 of the slanting slots.

The application pressure springs Ill because of their tension tend always to force the clutch plates 3 and 4 away from each other and thereby cause the clutch surfaces 5 and 6 to be applied against the adjacent drum surfaces. Under disengaging conditions (Figx2), this is prevented by the retracting force of the constricting springs l2 acting on the weights H and through the aforementioned levers l4 and roilersl'l and I8 contacting the sides of the slots l9 and 20. If the number of revolutions of the inner clutch part now increases, the centrifugal weights ll, due to their centrifugal force. constantly becoming greater, will swing out around their link bolts 1 against the force of the constricting springs l2, thus swinging the levers l4 toward the other end of the slots I9 and 20. Because of the widening out of the slanting slots l9 and 20, as the levers l4 move therein, the angle rings l5 and i5, and with them the clutch plates 3 and 4 are permitted to move axially under the pressure of the springs l0, and the annular surfaces 5 and Bare applied against the outer clutch parts l-2. This state of the clutch is shown in Fig. 3. The weights H are all the way out and the respective pivotal axes l3 and I are located exactly in a radial line from the central axis so that an increase in the speed of rotation will have no further effect on the position of the weights.

As the number of revolutions of the clutch diminishes, the constricting force of the springs l2 becomes stronger in relation to the centrifugal force of the weights II and tends to retract the latter. However, since the constricting force exerts its pressure centrally through the pivots I3 and 1 toward thecentral axis along radial lines, the retracting force is not effective to move the weights'to retracted position and the clutch re-- mains engaged. A separate device is therefore provided for initiating disengagement of the clutch. This .devioe comprises a second or auxof spring 22 stops 24 on the levers 23 come into contactwith the respective le'vers I4 and swing the latter with the main centrifugal weights ll out of the locked position of equilibrium. The force of the constricting spring 22 then acts directlyon the levers I 4 through the levers 23 to swing the same in the direction to cause disengagement of theclutch and the force the constricting springs I2 is added to the force of the constricting spring 22 and throw the weights ll to retracted position. Due to arrangement of the slanting slots l9 and 20, the clutch plates 3' and I are thereby drawn towards each other against the application pressure of the springs in. In Fig, 4 is seen the position of the slanting slots and the levers I I when the clutch is disengaged, and in librium of forces between the centrifugal weights Fig. 5, the pgsition of the slanting slots and levers ll when the clutch is engaged.

As will be seen, by selection of the proper strength springs and size of weights, it is easily possible to produce a clutch in which the equill andthe constricting springs l2, (by means of which the engagement number of revolutions is determined) occurs at a higher number of revo- -'lutions than the equilibrium of forces between the centrifugal weights 2| and the constricting spring 22 (by means of which the disengagement number of revolutions is determined) so that they clutch will engage at one speed and disengage at a different and lower speed, as desired.

Figs. 6 to 8 show another constructional example of a centrifugalclutch'similar to that shown in Figs. 1 to 5, except that different means are provided for initiating disengagement at the lower speed. In order to engage the clutch at a definite number of revolutions per minute, the centrifugal weights II and the two constricting I springs l2 are arranged as in Figs. 1. to 5. Howaaavoz lower number of revolutions perminute than the engagement.

In the form of the invention shown in Figs. 9 to 12, the two clutch plates 3', l are drawn towards each other by means of alined oppositely rotation of the sleeves 3! the plates 3' and 4' are either drawn towards each other against the pressure of the application pressure springs Ill, or are let iree to be moved apart by the springs lil'- to engaging position. Figs. 9 to 11 show the plates drawn together. The hollow studs 29 and.

30 form also a housing for expansion springs Ill.

The weights H are likewise pivotally ,sus-

pended on pins 32 carried by fln-like arms 33 projecting from rocking sleeves 34 mounted to turn on telescoping tubular guides or easing members 35 and 36. The tubular guides 35 and 36 are rigidly joined attheir ends to the respective clutch plates 3' and 4' and serve also as guide members-for the two plates in their axial movement and housings for pressure applying springs I. On the projections. 33, in addition to the pins 32, studs 31 are likewise mounted each of these resting against an arm 38 carried by the ever in contrast to the constructional form according to Figs. 1 to 5, pawl-like inwardly directed extensions are provided on three of the levers ll carrying the weights H, these being indicated as levers M in Figs. 'land 8. Centrifugal weight levers 26 pivoted atone end on studs 21 carried on hub 8 are arranged to contact the pawlends 25 of the levers l4 and are provided with notches 26' in which the ends 25 engage when the weights II and levers l4 and I4 swing to clutch engaging position. The levers and slots l9 and 20 are arranged so that in the'eng'aged position the levers stop against the ends of slots l9 and 20 by means of rollers ll before a common radial alinernent of the pivots I and I3 is attained. Thus the radii. passing through the respective pivots 'I and I3 are at an angle a (Fig.- 8) so that the retracting force of thetwo constricting springs l2, always has the possibility of retracting the weights ll respective nuts 3|. The pitch of the threads on -.the studs 23 and and in the nuts 3] is such that they do not possess a self locking action but will effect rotation of the nuts 3| under the force of the springs l0 acting to separate the plates when the centrifugalforce becomes less. This retraction is prevented by engagement of the pawl-like extensions 25 of the levers H in the notches 26' provided in levers 25, in the engaged position of the clutch (Fig. 8). By the singlesided. suspension of the levers 26 on the studs 21, a centrifugal force is produced in the levers that .holds the levers 25 in locking position with re spect to the levers H thus keeping the clutch in engagement upon a decrease in speed of rotation below the speed of engagement. The greater the weight of the levers 26, the longer the holding effect will remain effective.

L The pawlends 25 and notches 25" are shaped;

so that at ,adeslredlower speed, the constricting force of the springs 12 will cause the pawl ends to ride out of the notches- 26 against the force of weights 2.5 and permitthe clutch to disengage." The centrifugal force ofthe levers 26 can be suppl Win-5153118191011 0f f n 23 nd r pawls 40 that are mounted on pivots 4| in the the sleeve nuts 3|.

3' and 4' if the nuts are not held against rotation or positively rotated in the counter direction. In

this clutch there are six of these stud'and nut assemblies arranged between the two clutch plates 3"and 4' and between each assembly is a pair of guide tubes 3536. g

During operation, with increasing number of revolutions,,the weights ll swing out'against the constricting force of springs 39 and through connection to arms 33 rock the sleeves 34 in the.

clockwise direction and move studs 31 outwardly thus releasing the pressure 'on the arms 38 of The release of pressure on the arms 38 permits thesleeves 3] to rotate in the counterclockwise direction under the influence of the force of springs I0 acting to move the plates apart-as the arms 38 follow the studs 31. Thus as the weightsswing out, the plates-3" and 4' are iorced apart until the clutch is engaged.

In Fig. 12 a weight ii is shown in .the thrownout, position. As can be seen the clutch is' constructed so that the weights cannot reach the point at which the pivot 32 and axis of the sleeve '34would bev in'radial alinement but are stopped so that the pivot line remains inclined in the direction of disengagement the angle Upon decreasing number of revolutions; the constrictin'g springs 33 will'be able to force the weights again directly to the disengaging position. In order however to obtain a difference between the speed of engagement and the speed of disengagement the weights 1 I are held. in the engaging position by means of locking detentifl carried -'by the rocking sleeves 34. and'pivoted locking the free end of each o1 'them. It is likewise D S-2 sible with. this 1 arrangement therefore to effect the disengagement of the clutch at any desired hub section 3'. The locking pawls 40 are biased to locking position under pressure of a spring 42. Onlyjwhen the number. of revolutions has sunkso greatly that the pressure of the two constricting springs 39, tending to separate the detents 43 from the locking pawls 40, overcomes the resistance of springs of the pawls 4|], will disengagement of the clutch occur. This takes place in the following manner: upon retraction of the weights II, the studs 31 on the projections 33 turn back the nuts 3! by pressure on the arms 38 in the clockwise direction and thereby draw the clutch plates together against the tension of the application pressure springs Ill.

The clutch plates 3', 4' are mounted to slide axially on pins carried by the hub 8', these serving also to transmit the driving torque between the plates and the hub.

While preferred embodiments of the invention have been shown and described by way of illustration, various other modifications and changes in the details of construction may be resorted to without departing from the invention within vehicles, an outer clutch member, a pair of paral-' lel clutch plates disposed in axially spaced rela- Y tion and movable axially in opposite directions to engage and disengage said outer clutch member, a plurality of centrifugal weights arranged in circumferentially spaced relation between said plates and movable in paths parallel to said plates, spring means common to all of said weights for biasing said weights to a retracted position against centrifugal force, said weights being movable outwardly by centrifugal force upon attainment of a desired number of revolutions per minute, spring means exerting a separating force on said plates to move them into engagement with said outer clutch member, connections between said weights and said plates traction of said plates toward each other or permit separatory movement thereof.

5. In a centrifugal clutch of the character described, an outer clutch member, a pair of parallel clutch plates disposed in axially spaced relation and movable axially in opposite directions to engage and disengage said outer clutch member, a plurality of circumferentially spaced centrifugal weights disposed between said plates and movable in paths parallel to said plates, constricting spring means biasing said centrifugal weights to retracted position against centrifugal force until a given speed is reached, expansion effective to draw said plates toward each other when said weights are moved to retracted position by said biasing spring means and to permit separation of said plates by said spring means acting thereon when said weights move outwardly under centrifugal force.

2. In a. centrifugal clutch according to claim 1,

- lever means for mounting said centrifugal weights, said lev'ers being mounted so that said weights in their centrifugal movement outwardly swing in a direction counter to the direction of rotation of the clutch.

3. A centrifugal clutch according to claim 1 in which said connections between said weights and said plates comprise pivoted levers 'on which said weights are suspended, axially overlapping flange members carried by said plates, said flange members having divergent guiding cam slots disspring means exerting a separating force on said plates in the axial direction tending to move the same into gripping relation with said outer clutch member, opposed oppositely threaded studs carried by the confronting faces of said plates, rotatable nut members having oppositely threaded ends engaging said studs, means for effecting rotation of said nuts in opposite directions in response to inward or outward movement of said weights comprising a plurality of telescoping guide members carried by said plates, rocker arms journalled on said guide members, said weights being carried by said rocker arms, and connections between said rocker arms and said nuts.

.6. A centrifugal clutch according to claim 5 in which said telescoping guide members and said threaded studs are of tubular form and said ex pansion springs acting between said plates are disposed therein.

7. In a centrifugal clutch according to claim 1, a plurality of swinging arms for mounting said weights, articulated connections between said 8. In a centrifugal clutch of the character described, an outer clutch member, aghub member, a. pair of parallel clutch plates carried by said hub member in axially spaced relation and movable axially in opposite directions to engage and disengage said outer clutch member, a series of lever arms pivoted on said hub member beposed in overlapping relation and through which said pivoted levers extend whereby movement of said levers in said slots under the influence of said weights controls the movement of said clutch plates; W

4. A centrifugal clutch according to claim 1' in which said connections between said weights and said plates comprise oppositelyv threaded studs carried by the confronting surfaces of said plates, rotatable-nut members having oppositely threaded ends for engaging. threadedly opposed studs on the respective plates, and means for tween said plates to swing .in a plane parallel 'to said'plates, centrifugal weights pivotally connected to the free ends of said lever arms. said weights being arranged to form a .ring between said plates,: constricting springs encircling said weights and biasing said weights andlever arms to a retracted position against the action of centrifugal force, said weights and arms being arranged so that upon swinging outwardly to clutch v engaging position said weights and arms "occupy. a neutral position of equilibrium from which said translating movementpf said weights into rotary motion of said nuts whereby to effect re- 76 on said hub member, centrifugal weights carried -.'constricting springs are ineffective to return them to retracted position, expansion 's'pi-ing. means betweensaid plates exerting an axial separating'force thereon to move said plates into engagement with said outer clutch member, connections between said lever arms and said' plates for moving said plates toward each other against the action of said expansion springs when said weights and arms are retracted by said constrictin'g springs, as second series of lever arms pivoted v I 2,263,70? by said second series of lever arms, constricting spring means acting on said last mentioned plates toward-each other against the-action of.

weights to bias them to retracted position, means 1 on the lever arms or said second series adapted to engage the lever arms of said first mentioned series upon-inward movement of said last mentioned weights to initiate movement of said first mentioned arms and weights from said neutral. position of equilibrium in the-direction of retraction. g 9. In a centrifugal clutch of the character described, an outer clutch member, a hub member,

a pair of parallel clutch plates carried by said said expansion spring means whensaid weights and arms are'retracted and to permit separation of said plates by said expansion spring means when said weights and arms swing outwardly by centrifugal force, means. for latching said arms and weights in the outermost position thereof against, the retracting force of said constricting spring, and centrifugal means for re-' leasing said weights from latched position at a selected speed of rotation less than the speed of rotation necessary to effect movement of said hub member in axially spaced relation and'movable axiallyin opposite directions to engage and disengage said outer clutch member, a series of lever arms pivoted on said .hub member between said plates to swing in a' plane vparallel'to said plates, centrifugal weights pivotally connected to the free ends of said lever arms, said weights being arranged to form a ringbetween-said plates. weights and biasing said weights andlever arms to a retracted position against the action of centrifugal force, said weights and arms being arranged so. that upon swinging outwardly to I ,clutch engaging position said weights and arms occupy 'a neutral position of equilibrium from which said constricting springs are ineiiective to return them to retracted position, expansion.

spring means between said plates exerting an connectiensbetween said leverarms and said plates for moving said plates toward each other against the action of said expansion springs when said weights and arms are retracted by said constricting' springs, and centrifugal means operative at a lower speed thanthatnecessary to effect movement of said centrifugal weights and arms to saidneutral position of equilibrium for releasing said arms and weights from'said position.

10. In acentriiugal clutch of the character described, an outer clutch member, a hub memher, a pair of parallel clutch plates carried by constricting springs .encircling said weights and arms to latching position 11. A clutch according to claim 10 inwhlch said latching means comprises a:pawl end on said lever arms, auxiliary centrifugal weights disengage said outer member, expansion spring axial separating force thereon to. move said plates into engagement with said outer clutch member,

said "hub member in axially spaced relation and sage anddisengage said outer clutch member,

expansion spring means exerting a'separating asialforce on said plates tending to move them into eng gement with said outer clutch member, a series of lever arms pivoted onsaid hub, centrifugai weights pivoted on the outer ends of said arms. saidarms beingpivoted to swingin a plane mane: to said plates. c nstricting spring means acting on said weights to move the same and arm's to a retracted position against fcrce,iconneetions said arms for axial movement in opposite directions to en-v fallsto a predetermined speed of engagement.

means acting between-said plates to move them apart and into engagement with said outerclutch member, opposed oppositely threaded studs carried by said plates, a nut having oppositely.

threaded ends enga ngsaid studs whereby rota- -.tion of said nuts in one direction draws said plates together to retracted position against the action of said expansion spring means and rota-v tion in the other direction frees said plates for separation by said spring means, a plurality of swinging arms carried by saidwhub between said plat'es,- centrifugal weights carried by said arms, constricting spring means acting on said weights, connections between said arms and said nuts for rotating said nuts in the plate retracting direction when said weights are retracted'by said con stricting spring means and for permittingrotation of said nuts in the plate releasing direction when said weights swing out against the action of said, constricting spring means, means for latching said weights in said last mentioned position andelective to retain said weights in said position until the speed of rotation of saidclutch speed lower than the 1s. a centrifugal clutch according in claim 1':

inwhichsaidlatchingmeanscomprisesadetent -carriedbysaidswingingarmsandpivotedspringf tensioned latch members carried by said hub for latching engagement with said detents.

and; said clutch plates mm to move we 

